Because of the lack of restrictions in Unlimited, decks can use combinations of cards which are not legal in Standard format or Expanded format play. Cards such as Porygon2 and Seeker which never appeared in the same Standard format, are frequently used together. Despite the large variety of cards available, only a few strategies make up what is generally considered the highest "tier" in Unlimited play, with most competitive decks being either "donk" decks focused on winning by removing all of the opponent's Pokémon from play, or "lock" decks focused on preventing the opponent from using attacks, abilities, and Trainer cards.